Electrotherapy device and method

ABSTRACT

Electrical muscle stimulation is effected by means of a body garment having a plurality of body contact electrodes secured in it. The garment is wired to provide a single contact area for all the electrodes. The electrodes are selectively energized through a multiple contact switch associated with said contact area, so that the electrical muscle stimulating pulse output of a generator may be applied to a desired electrode pair through the switch.

[0001] The present invention relates to a device for attachingelectrodes to a subject for stimulating abdominal muscles byelectrotherapy, and the invention also relates to a device forstimulating abdominal muscles by electrotherapy. The invention furtherrelates to an electrotherapeutic method for stimulating abdominalmuscles, and to a fastener for use in the device.

[0002] Electrotherapy is commonly used for stimulating abdominal musclesfor improving and toning the muscles, and for the relief of pain. Knownelectrotherapeutic methods and devices require that a pulsed signal bepassed subcutaneously through the subject between a pair of electrodeswhich typically, are aligned with the muscle to be stimulated fordefining a current path between the electrode which is colinear with thedirection of the muscle. In known electrotherapeutic devices andmethods, it is necessary to provide a relatively large number ofelectrode pairs for stimulating the more important abdominal muscles,for example, the central rectus abdominis muscle, and the transversalisand oblique muscles. Typically, one or two pairs of electrodes arerequired located on respective opposite sides of the umbilicus forstimulating the rectus abdominis muscle, and two obliquely locatedelectrode pairs are required towards the respective sides of theabdominal region for stimulating the transversalis and oblique muscleson the respective sides of the abdomen. Thus, in order to stimulate therectus abdominis muscle, the transversalis and oblique muscles, three tofour electrode pairs are required. This, leads to a number ofdisadvantages, in that firstly, unless extreme care is taken in locatingthe electrodes on the abdomen of the subject some or all of theelectrodes can readily easily be misaligned with the respective musclesor displaced therefrom, thus, leading to significant inefficiencies andindeed in extreme cases ineffectual treatment. Secondly, because of thehigh number of electrode pairs, a relatively complex signal generator isrequired for providing appropriately pulsed signals so that the pulsedsignals only travel between the respective pairs between which thepulsed signals are to travel subcutaneously in the subject. Thirdly, inmany cases there is a danger of transthoracic current paths beingdefined by the electrodes, which in certain cases can lead totransthoracic currents within the subject, which in extreme cases maycause cardiac arrhythmias. The possibility of misalignment of theelectrode pairs further increases the risk of transthoracic currentsbeing passed through the subject.

[0003] There is therefore a need for a device for attaching electrodesto a subject for stimulating abdominal muscles and in particular forstimulating the rectus abdominis, the transversalis and the obliquemuscles, which overcomes these problems. There is also a need for anelectrotherapeutic device and a method for stimulating abdominal muscleswhich overcomes these problems.

[0004] The present invention is directed towards providing such a devicefor attaching electrodes to a subject, such an electrotherapeutic deviceand method for stimulating abdominal muscles of a subject. The inventionis also directed towards providing a fastener for use in the device.

[0005] According to the invention there is provided a device forattaching at least three electrodes to a subject for stimulatingabdominal muscles of the subject, the device comprising an attachmentmeans for extending around the torso of the subject, wherein a mainlocating means is provided on the attachment means for locating acentral electrode of the at least three electrodes adjacent theumbilicus of the subject, and two secondary locating means are providedon the attachment means disposed on respective opposite sides of themain locating means for locating two corresponding side electrodes ofthe at least three electrodes spaced apart from the central electrode ina general direction towards a corresponding one of the left and rightmid-axillary lines of the torso intermediate the rib cage andcorresponding left and right iliac crests so that by applying at leastone pulsed signal to the subject through the respective central and sideelectrodes abdominal muscles of the subject are stimulated.

[0006] In one embodiment of the invention the secondary locating meansare disposed on the attachment means for locating the respective sideelectrodes towards the mid-point of the corresponding mid-axillary linebetween the rib cage and the corresponding iliac crest. Preferably, thesecondary locating means are disposed on the attachment means forlocating the respective side electrodes adjacent the correspondingmid-axillary line.

[0007] Ideally, the secondary locating means are disposed on theattachment means for locating the respective side electrodes adjacentthe mid-point of the corresponding mid-axillary line between the ribcage and the corresponding iliac crest.

[0008] Preferably, the main locating means is disposed on the attachmentmeans for locating the central electrode on the umbilicus and extendingaround the umbilicus. Advantageously, the main locating means isdisposed on the attachment means for locating the central electrode onthe umbilicus and extending completely around the umbilicus.

[0009] In one embodiment of the invention the main locating means isdisposed on the attachment means for locating the central electrode onthe umbilicus, but with a greater area of the central electrode locatedbelow the umbilicus than above the umbilicus.

[0010] In another embodiment of the invention the main locating means isdisposed on the attachment means for locating the central electrodeadjacent but not on the umbilicus.

[0011] In a further embodiment of the invention the main locating meansis disposed on the attachment means for locating the central electrodebelow the umbilicus.

[0012] In a still further embodiment of the invention the main locatingmeans is disposed on the attachment means for locating the centralelectrode above the umbilicus.

[0013] In a further embodiment of the invention the main locating meansis disposed on the attachment means for locating the central electrodeboth below and above the umbilicus.

[0014] In one embodiment of the invention a reference means is providedon the attachment means for locating the attachment means on the torsorelative to an anatomical reference. Preferably, the reference means isprovided for locating the attachment means circumferentially around thetorso. Advantageously, the reference means is provided for locating theattachment means vertically along the torso.

[0015] In one embodiment of the invention the main locating means actsas the reference means for locating the attachment means relative to theanatomical reference provided by the umbilicus.

[0016] In another embodiment of the invention the main locating meanscomprises a first main locating means and a second main locating meansfor locating respective corresponding first and second centralelectrodes adjacent the umbilicus of the subject.

[0017] Advantageously, the first main locating means is provided forlocating the first central electrode above the umbilicus, and the secondmain locating means is provided for locating the second centralelectrode below the umbilicus.

[0018] In another embodiment of the invention two sets of at least twosecondary locating means are disposed on the respective opposite sidesof the main locating means for facilitating selective location of therespective side electrodes for accommodating different girths of torso.

[0019] Advantageously, each set of secondary locating means comprisesthree secondary locating means.

[0020] In another embodiment of the invention portions of the attachmentmeans on respective opposite sides of the main locating means betweenthe main locating means and the corresponding secondary locating meansare of resilient material for facilitating resilient stretching of theattachment means between the main and corresponding secondary locatingmeans. Preferably, the attachment means is of a resilient material forfacilitating stretching of the attachment means around the torso, theresilient portions of the attachments means being of greaterstretchability than that of the rest of the attachment means.

[0021] In one embodiment of the invention a main electrically conductivecontact means is provided on the attachment means corresponding to eachmain locating means for receiving the at least one pulsed signal and forrelaying the signal to the corresponding central electrode. Preferably,each main contact means is located within the corresponding mainlocating means.

[0022] In another embodiment of the invention two secondary electricallyconductive contact means are provided on the attachment means forreceiving the at least one pulsed signal and for relaying the signal tothe respective corresponding side electrodes. Advantageously, eachsecondary contact means is located adjacent the corresponding secondarylocating means or the corresponding set of secondary locating means.

[0023] In another embodiment of the invention each secondary contactmeans is located adjacent the corresponding set of secondary locatingmeans so that irrespective of which secondary locating means is selectedfor locating the corresponding side electrode the side electrode is inelectrically conductive engagement with the secondary contact means.

[0024] Advantageously, each main and secondary locating means isprovided by a visually perceptive locating means. Preferably, each mainand secondary locating means is formed by a corresponding locating markon the attachment means.

[0025] Ideally, each locating mark defines an outline of a part of theperiphery of the corresponding electrode corresponding to the locatingmeans.

[0026] In one embodiment of the invention each locating means is adaptedfor locating a patch type electrode.

[0027] In another embodiment of the invention the device comprises theat least three electrodes. Preferably, each electrode is a patch typeelectrode.

[0028] In one embodiment of the invention each side electrode is sizedto cover at least a portion of the corresponding lower thoracic nervesand the corresponding first and second lumbar nerves.

[0029] In another embodiment of the invention each central electrode issized to extend substantially across the rectus abdominus muscle.

[0030] Advantageously, each electrode defines an area of contact overwhich the electrode makes direct electrical contact with the subject,the area of contact of each side electrode being such as not to exceedthe area of contact of the or both central electrodes. Preferably, thearea of contact of each side electrode does not exceed one third of thearea of contact of the or both central electrodes.

[0031] In one embodiment of the invention each side electrode is ofwidth in a circumferential direction relative to the torso of thesubject in the range of 50 mm to 150 mm, and is of length in a verticaldirection relative to the torso of the subject in the range of 80 mm to120 mm.

[0032] In one embodiment of the invention a first electricallyconductive coating is provided on one side of each electrode forelectrically connecting the electrode to the corresponding contactmeans. Advantageously, the first coating is a gel type coatingcontaining an electrolyte solution for enhancing electrical contactbetween the electrode and the corresponding contact means.

[0033] In another embodiment of the invention a second electricallyconductive coating is provided on the other side of each electrode forelectrically connecting the patch electrode and the torso of thesubject. Preferably, the second coating is a gel type coating.

[0034] In one embodiment of the invention the second coating is anadhesive coating.

[0035] In another embodiment of the invention the first coating is anadhesive coating.

[0036] Advantageously, the bond strength of the first coating to theattachment means is greater than the bond strength of the second coatingto the torso for facilitating removal of the attachment means and theelectrodes located thereon from the torso of the subject.

[0037] Preferably, the electrodes are pre-coated with the respectivefirst and second adhesive coatings.

[0038] In one embodiment of the invention a receiving means is providedin the attachment means for receiving a signal generating means forgenerating the at least one pulsed signal.

[0039] Preferably, a main electrical connecting means extends betweenthe receiving means and each main contact means for relaying the atleast one pulsed signal from the signal generating means to thecorresponding main contact means.

[0040] Advantageously, a secondary electrical connecting means extendsbetween the receiving means and each secondary contact means forrelaying the at least one pulsed signal from the signal generating meansto the corresponding secondary contact means.

[0041] Ideally, each electrical connecting means is located within theattachment means.

[0042] In one embodiment of the invention the receiving means is areleasable receiving means for releasably receiving the signalgenerating means.

[0043] Advantageously, the receiving means receives the signalgenerating means with a snap fit action.

[0044] In one embodiment of the invention the signal generating meansfor generating the at least one pulsed signal is provided in thereceiving means.

[0045] In one embodiment of the invention a means is provided forselectively selecting at least one pair of electrodes from the at leastthree electrodes through which the at least one pulsed signal is appliedto the subject.

[0046] In another embodiment of the invention the at least one pulsedsignal is applied simultaneously to each of the selected pairs ofelectrodes. Alternatively, the at last one pulsed signal is appliedsequentially to each of the selected pairs of electrodes.

[0047] In one embodiment of the invention one of the selected pairs ofthe electrodes comprises one side electrode and the central electrode,and another selected pair of the electrodes comprises the other sideelectrode and the central electrode.

[0048] In another embodiment of the invention one of the selected pairsof electrodes comprises the two side electrodes.

[0049] In another embodiment of the invention one of the selected pairsof electrodes comprises one of the side electrodes and one of the firstand second central electrodes, and another of the selected pairs ofelectrodes comprises the other of the side electrodes and the other ofthe first and second central electrodes.

[0050] In a further embodiment of the invention one of the selectedpairs of electrodes comprises the first and second central electrodeswhich act as one single electrode and one of the side electrodes, andanother of the selected pairs of electrodes comprises the first andsecond central electrodes which act as one single electrode and theother side electrode.

[0051] In a still further embodiment of the invention one of theselected pairs of electrodes comprises the first and second centralelectrodes.

[0052] In one embodiment of the invention the pulsed signals generatedby the signal generating means for applying to the respective pairs ofelectrodes may be the same or different.

[0053] In one embodiment of the invention each pulsed signal comprises aplurality of pulses at intervals in the range of 5 milliseconds to 1000milliseconds. Preferably, each pulsed signal comprises a plurality ofpulses at intervals in the range of 20 milliseconds to 40 milliseconds.

[0054] Advantageously, each pulsed signal comprises a plurality ofpulses at intervals of approximately 30 milliseconds±20%. Preferably,the interval between pulses of each pulsed signal is adjustable.

[0055] In another embodiment of the invention each pulsed signalcomprises pulses of duration in the range of 10 microseconds to 200000microseconds. Advantageously, each pulsed signal comprises pulses ofduration in the range of 50 microseconds to 1000 microseconds.

[0056] Preferably, each pulsed signal comprises pulses of duration inthe range of 100 microseconds to 500 microseconds. Ideally, each pulsedsignal comprises pulses of duration of approximately 300milliseconds±20%. Preferably, the duration of each pulsed signal isadjustable.

[0057] In another embodiment of the invention each pulsed signalcomprises a plurality of pulses of magnitude in the range of 0 mA to 100mA. Preferably, the magnitude of each pulse of each pulsed signal isadjustable.

[0058] In one embodiment of the invention the attachment means comprisesa belt.

[0059] In another embodiment of the invention a securing means isprovided on the belt for securing the belt around the torso of thesubject.

[0060] In a further embodiment of the invention a main fastening meansis provided corresponding to each main locating means for fastening acorresponding central electrode to the attachment means adjacent thecorresponding main locating means.

[0061] In a still further embodiment of the invention two secondaryfastening means are provided in the attachment means for fastening therespective side electrodes to the attachment means adjacent thecorresponding selected secondary locating means.

[0062] In one embodiment of the invention each fastening means comprisesa stud fastener.

[0063] In another embodiment of the invention each stud fastenercomprises a female part and a male part, the female part being securedto the attachment means.

[0064] In a further embodiment of the invention each stud fastener iselectrically conductive so that the female part of the stud fastenersform the corresponding contact means.

[0065] Preferably, an exposed surface of the female part of each studfastener is of electrically insulating material.

[0066] Advantageously, the exposed surface of each female part of eachstud faster is coated with an electrically insulating coating.

[0067] Additionally, the invention provides a stud fastener for use inthe device according to the invention, the stud fastener comprises amale part for attaching to a corresponding electrode, and a female partfor attaching to the attachment means.

[0068] In one embodiment of the invention the male and female parts ofthe stud fastener engage each other with electrically conductiveengagement.

[0069] In another embodiment of the invention an exposed externalsurface of the female part of the stud fastener which abuts the malepart of the stud fastener is of electrically insulating material.

[0070] In a further embodiment of the invention the electricallyinsulating material is provided by an electrically insulated coating onthe exposed abutting surface.

[0071] The invention further provides a method for stimulating abdominalmuscles of a subject, the method comprising passing at least one pulsedsignal subcutaneously through the subject between selected electrodes ofat least three electrodes, one of the at least three electrodes being acentral electrode located adjacent the umbilicus of the subject, and theother two electrodes being side electrodes located on the subject spacedapart from the central electrode on respective sides thereof in ageneral direction towards a corresponding one of the left and rightmid-axillary lines of the torso intermediate the rib cage andcorresponding left and right iliac crests.

[0072] In one embodiment of the invention each side electrode is locatedtowards the mid-point of the corresponding mid-axillary line between therib cage and the corresponding iliac crest. Preferably, each sideelectrode is located adjacent the corresponding mid-axillary line.Ideally, each side electrode is located adjacent the mid-point of thecorresponding mid-axillary line between the rib cage and thecorresponding iliac crest.

[0073] Preferably, the central electrode is located on the umbilicus andextends around the umbilicus. Advantageously, the central electrode islocated on the umbilicus and extends completely around the umbilicus.

[0074] In one embodiment of the invention the central electrode islocated on the umbilicus, but with a greater area of the centralelectrode located below the umbilicus than above the umbilicus.

[0075] In another embodiment of the invention the central electrode islocated adjacent but not on the umbilicus.

[0076] In a further embodiment of the invention the central electrode islocated below the umbilicus.

[0077] In a still further embodiment of the invention the centralelectrode is located above the umbilicus.

[0078] In another embodiment of the invention the central electrode islocated both below and above the umbilicus.

[0079] In a still further embodiment of the invention the centralelectrode is provided by two electrodes, namely, a first centralelectrode and a second central electrode, both of which are locatedadjacent the umbilicus. Preferably, the first central electrode islocated above the umbilicus and the second central electrode is locatedbelow the umbilicus.

[0080] In one embodiment of the invention the at least one pulsed signalis applied to the subject so that the signal passes subcutaneouslythrough the subject between at least one selected pair of the at leastthree electrodes.

[0081] In one embodiment of the invention the at least one pulsed signalis applied simultaneously to each of the selected pairs of electrodes.Alternatively, the at last one pulsed signal is applied sequentially toeach of the selected pairs of electrodes.

[0082] In one embodiment of the invention one of the selected pairs ofelectrodes comprises one side electrode and the central electrode, andanother selected pair of electrodes comprises the other side electrodeand the central electrode.

[0083] In another embodiment of the invention one of the selected pairsof electrodes comprises the two side electrodes.

[0084] In a further embodiment of the invention one of the selectedpairs of electrodes comprises one of the side electrodes and one of thefirst and second central electrodes, and another of the selected pairscomprises the other of the side electrodes and the other of the firstand second central electrodes.

[0085] In a still further embodiment of the invention one of theselected pairs of electrodes comprises the first and second centralelectrodes which act as one single electrode and one of the sideelectrodes, and another of the selected pairs of electrodes comprisesthe first and second central electrodes which act as one singleelectrode and the other side electrode.

[0086] In a further embodiment of the invention one of the selectedpairs of electrodes comprises the first and second central electrodes.

[0087] In one embodiment of the invention the pulsed signals applied tothe respective pairs of electrodes may be the same or different.

[0088] In one embodiment of the invention each pulsed signal comprises aplurality of pulses at intervals in the range of 5 milliseconds to 1000milliseconds. Preferably, each pulsed signal comprises a plurality ofpulses at intervals in the range of 20 milliseconds to 40 milliseconds.Advantageously, each pulsed signal comprises a plurality of pulses atintervals of approximately 30 milliseconds±20%.

[0089] Ideally, the interval between pulses of each pulsed signal isadjustable.

[0090] In one embodiment of the invention each pulsed signal comprisespulses of duration in the range of 10 microseconds to 200000microseconds. Preferably, each pulsed signal comprises pulses ofduration in the range of 50 microseconds to 1000 microseconds.

[0091] Advantageously, each pulsed signal comprises pulses of durationin the range of 100 microseconds to 500 microseconds. Ideally, eachpulsed signal comprises pulses of duration of approximately 300milliseconds±20%. Preferably, the duration of each pulsed signal isadjustable.

[0092] In another embodiment of the invention each pulsed signalcomprises a plurality of pulses of magnitude in the range of 0 mA to 100mA. Preferably, the magnitude of each pulse of each pulsed signal isadjustable.

[0093] Further the invention provides an electrotherapeutic device forstimulating muscles of a muscle group of a subject, the devicecomprising a plurality of electrodes for placing on the subject forapplying at least one pulsed signal to the subject for stimulating themuscles, a signal generating means for generating the at least onepulsed signal, and a selecting means for selectively selecting theelectrodes in electrode pairs and for selectively applying the at leastone pulsed signal to the selected electrode pairs for selectivestimulation of the muscles of the muscle group.

[0094] In one embodiment of the invention the selecting means comprisesa switching means for selectively switching the at least one pulsedsignal from the signal generating means to the electrodes.

[0095] Additionally, the invention provides a method for stimulatingmuscles of a muscle group of a subject, the method comprising passing atleast one pulsed signal subcutaneously through the subject betweenselected electrodes of at least three electrodes, wherein the electrodesare selectively selected in electrode pairs for selectively stimulatingselected muscles of the muscle group.

[0096] In one embodiment of the invention the electrode pairs aresequentially selected from the electrodes. Alternatively, the electrodepairs are simultaneously selected from the electrodes.

[0097] The advantages of the invention are many. An important advantageof the invention is that it permits relatively accurate placement andalignment of the electrodes on the subject. A particularly importantadvantage of the invention results from the fact that the deviceaccording to the invention permits relatively accurate placement of theelectrodes on the subject, and because of this, it has been found thatwith only three electrodes the device according to the inventionprovides adequate stimulation to the abdominal muscles, and inparticular, to the rectus abdominis and the transversalis and obliquemuscles, particularly, for the purpose of toning the muscles. It hasbeen surprisingly found that by locating the central electrode adjacentthe umbilicus, and the respective side electrodes towards thecorresponding mid-axillary lines to the respective left and right sidesof the central electrode good stimulation of the abdominal muscles isachieved. However, it has been found that the closer the side electrodesare located to the corresponding left and right mid-axillary lines thebetter will be the stimulation. Indeed, it has been found that optimumstimulation is achieved by locating the respective side electrodes oncorresponding lines extending from the umbilicus to the mid-point on thecorresponding left and right mid-axillary lines between the rib cage andthe corresponding iliac crest. In general, it has been found the maximumstimulation of the rectus abdominis, the transversalis and the obliquemuscles is achieved when the side electrodes are located on thecorresponding mid-axillary line substantially midway between the ribcage and the iliac crest. A further advantage of the invention isachieved where first and second central electrodes are provided, oneabove and the other below the umbilicus where it has been found thateven greater stimulation of the abdominal muscles is achieved, and inparticular, stimulation of the rectus abdominis, the transversalis andthe oblique muscles.

[0098] By providing the side electrodes adjacent the mid-axillary lineor spaced part from the central electrode towards the mid-axillary line,but relatively close to the mid-axillary line the side electrodes applythe pulsed signal or signals to nerve trunks rather than nerve brancheswhich spread out from the nerve trunks. The electrical signals beingapplied to the nerve trunks, thus spread out through the nerve branchesfrom the nerve trunks, and are thus effective in stimulating asignificantly greater area of the muscles of the abdomen than if theelectrodes were placed over nerve branches as has been the caseheretofore. Additionally by placing the central electrode over oradjacent the umbilicus, and the side electrodes adjacent or relativelyclose to the mid-axillary line, the spacing between the central and sideelectrodes is such as to cause the pulsed signal or signals to traveldeeper through the subject beneath the fatty tissue. This, thus, resultsin the pulsed signal or signals being targeted at the deeper musclecontrolling nerves, thus providing more efficient stimulation of themuscles. Placing the electrodes relatively closely together, as has beenthe case heretofore, tends to cause the pulsed signal or signals to passrelatively near the surface of the skin, thus having little affect onthe deeper muscle controlling nerves. Indeed, a further advantage ofspacing the electrodes apart according to the invention is that theeffect of subcutaneous currents on the touch and pain nerves isminimised, thereby minimising discomfort to the subject. Additionally,by providing the side electrodes of size to extend across the lowerthoracic nerves and the first lumbar nerves adjacent the mid-axillaryline further efficiency is achieved by virtue of the fact that thepulsed signal or signals is applied to the nerve trunks of these nerves.A further advantage of providing the electrodes of reasonable size isthat the current density of the pulsed signal or signals passing throughthe electrodes, and in turn into the subject is minimised, thus, furtherminimising discomfort resulting from the effect of the subcutaneouscurrent on the touch and pain nerves. Indeed, by providing theelectrodes of reasonable size, a higher current may also be appliedthrough the electrodes if such should be desired with minimum discomfortto the subject.

[0099] A further advantage of the invention is that it is virtuallyimpossible to incorrectly attach or misapply the electrodes to thesubject, and furthermore, there is virtually no danger of the pulsedsignals being applied to the wrong electrodes, since the attachmentmeans is pre-wired with the main and secondary connecting means.

[0100] A further advantage of the invention is achieved when provisionis made for selectively selecting the electrodes into electrode pairs,in that individual muscles of muscle groups may be selectivelystimulated, and additionally, if desired different pulsed signals may beapplied to different selected electrode pairs.

[0101] The invention will be more clearly understood from the followingdescription of some preferred embodiments thereof which are given by wayof example only with reference to the accompanying drawings, in which:

[0102]FIG. 1 is a front elevational view of a torso of a subject,

[0103]FIG. 2 is a front plan view of a device according to the inventionfor stimulating abdominal muscles,

[0104]FIG. 3 is a rear plan view of the device of FIG. 2,

[0105]FIG. 4 is an exploded perspective view of a detail of the deviceof FIG. 2,

[0106]FIG. 5 is a rear plan view of a portion of the device of FIG. 2illustrating electrode pads positioned on the device,

[0107]FIG. 6 is a cut-away rear plan view of another portion of thedevice of FIG. 2,

[0108]FIGS. 7 and 8 are perspective views of respective electrodes ofthe device of FIG. 2,

[0109]FIG. 9 is a transverse cross-sectional view of the electrode ofFIG. 7 on the line IX-IX of FIG. 7,

[0110]FIG. 10 is a front elevational view of a torso of a subjectillustrating the device of FIG. 2 in use,

[0111]FIG. 11 is a front elevational view of the torso of the subject ofFIG. 10 illustrating the correct positioning of the electrodes of thedevice of FIG. 2,

[0112]FIG. 12 is a side elevational view of the torso of the subject ofFIG. 10 also illustrating the correct positioning of the electrodes ofthe device of FIG. 2,

[0113]FIG. 13 is a block representation of a circuit of the device ofFIG. 2,

[0114]FIG. 14 is a graphical representation of pulsed signals generatedby the device of FIG. 2,

[0115]FIG. 15 is a block representation of an alternative circuitarrangement of the device of FIG. 2,

[0116]FIG. 16 is a graphical representation of pulsed signals generatedby the device of FIG. 2 in the configuration of FIG. 15,

[0117]FIG. 17 is a block representation of an alternative circuitarrangement of the device of FIG. 2,

[0118]FIG. 18 is a graphical representation of pulsed signals generatedby the device of FIG. 2 in the configuration of FIG. 17,

[0119]FIG. 19 is a rear plan view of a device according to anotherembodiment of the invention for stimulating abdominal muscles,

[0120]FIG. 20 is a front elevational view of a torso of a subjectillustrating the device of FIG. 19 in use,

[0121]FIG. 21 is a front elevational view of the torso of the subject ofFIG. 20 illustrating correct positioning of electrodes of the device ofFIG. 19,

[0122] FIGS. 22 to 24 are block representations of alternativeconfigurations of the circuit of the device of FIG. 19,

[0123]FIG. 25 is a diagrammatic representation of subcutaneous currentpaths which may be developed in the subject using the device of FIG. 19,

[0124]FIG. 26 is a block representation of one circuit configuration ofthe device of FIG. 19,

[0125]FIG. 27 is a block representation of an alternative circuitconfiguration of the device of FIG. 19,

[0126]FIG. 28 is a rear plan view of a device according to anotherembodiment of the invention for stimulating abdominal muscles,

[0127]FIG. 29 is an exploded transverse cross-sectional view of a detailof the device of FIG. 28, and

[0128]FIG. 30 is a perspective view of a portion of a detail of thedevice of FIG. 28.

[0129] Referring to the drawings and initially to FIGS. 1 to 18 there isillustrated an electrotherapeutic device according to the inventionindicated generally by the reference numeral 1 for stimulating abdominalmuscles of a subject, and in particular, for stimulating the rectusabdominis, the transversalis and oblique muscles of the abdomen of thesubject for toning of the muscles. Before describing the device 1 theposition of the muscles in the abdominal wall of the subject will firstbe described with reference to FIG. 1.

[0130] Referring now in particular to FIG. 1 a torso 3 of a subject isillustrated. The abdomen 5 of the subject is located between the ribcage 6 and the pelvis 7 and between the left and right iliac crests 8and 9, respectively on the respective left and right sides 10 and 11,respectively of the subject. The umbilicus 12 is located centrally inthe abdomen 5. The left and right mid-axillary lines 13 and 14 extendbetween the left and right iliac crests and the rib cage 6 on the leftand right sides 10 and 11 of the torso 3. Rectus abdominis muscles whichare indicated by the reference numeral 15 extend substantiallylongitudinally from a position below the rib cage 6 to a position abovethe pelvis, while the transversalis muscles which are indicated by thereference numeral 16 extend transversely across the abdomen between theleft and right sides 10 and 11 thereof, while the oblique musclesindicated by the reference 17 extend obliquely between respectivepositions below the rib cage 6 to one side thereof and a centralposition adjacent the pelvis 7.

[0131] In known electrotherapeutic devices and methods, in order tostimulate these three muscles, namely, the rectus abdominis muscles 15,the transversalis muscles 16 and the oblique muscles 17 pulsed signalsare applied to the abdomen of the subject through four electrode pairs20 a and 20 b, 21 a and 21 b, 22 a and 22 b, 23 a and 23 b arranged asillustrated in FIG. 1. The electrode pairs 20 a and 20 b and 21 a and 21b stimulate the rectus abdominis muscles 15, while the electrode pairs22 and 23 a and b stimulate the transversalis muscles and obliquemuscles for toning thereof.

[0132] Referring now in particular to FIGS. 2 to 12 the device 1comprises an attachment means, namely, a belt 25 for extending aroundthe torso 3 of the subject for locating and retaining three electrodes,which in this embodiment of the invention are patch electrodes, namely,a central electrode 26 and a pair of side electrodes 27 adjacent theabdomen 5 for applying one or more pulsed signals generated by a signalgenerating means, namely, a signal generator 28 which is releasablylocated in the belt 25 as will be described below. A main locating meansand two sets of secondary locating means provided respectively by mainand secondary locating marks 29 and 30, respectively, are provided on aninner side 34 of the belt 25 for locating the central electrode 26 andthe side electrodes 27, respectively on the belt 25.

[0133] The main locating marks 29 define two opposite peripheral sidesof the central electrode 26 for defining a main locating area 31 forreceiving and locating the central electrode 26 for accurately locatingthe central electrode 26 on the belt 25 to in use lie centrally over theumbilicus 12. In this embodiment of the invention each set of secondarylocating marks 30 a, 30 b and 30 c define three respective secondarylocating areas 32 a, 32 b and 32 c at which the respective sideelectrodes 27 may be selectively attached to the belt 25 so that in usethe side electrodes preferably lie centrally over the corresponding oneof the left and right mid-axillary lines 13 and 14 of the subject and ona mid-point which is substantially midway between the rib cage 6 and thecorresponding one of the left and right iliac crests 8 and 9. Althoughin practice while it is desirable that the side electrodes 27 shouldline on the corresponding mid-axillary lines, it has been found that, ingeneral, adequate stimulation of the muscles is achieved if the sideelectrodes 27 are located on the belt 25 to lie on respective linesextending from the umbilicus to the mid-point of the correspondingmid-axillary lines and towards the mid-axillary lines. In thisembodiment of the invention the secondary locating marks 30 a, 30 b and30 c define a periphery 33 of one end of the corresponding sideelectrode 27 for indicating the three secondary locating areas 32 a, 32b and 32 c at which the side electrodes 27 may be located on the belt 25for accommodating torsos of different girth about the waist.

[0134] The main locating area 31 and the secondary locating areas 32 a,32 b and 32 c are arranged on the belt 25 so that when the centralelectrode 26 is located in the main locating area 31, and the sideelectrodes 27 are located in the appropriate one of the secondarylocating areas 32 a, 32 b or 32 c, and when the belt 25 is securedaround the torso 3 with the central electrode 26 located centrally overthe umbilicus 12 the respective side electrodes 27 are located over theleft and right mid-axillary lines 13 and 14, respectively, between therib cage 6 and the left and right iliac crests 8 and 9, or relativelyclose to the mid-axillary lines.

[0135] A securing means, in this embodiment of the invention provided byhooks and eyes of the type typically sold under the Trade Mark VELCRO isprovided at the respective ends 35 and 36 of the belt 25, a band ofhooks 38 of the hooks and eyes being provided on the inner side 34 atthe end 35, while bands of eyes 39 of the hooks and eyes are provided onthe outer side 40 at the end 36 of the belt 25. In this embodiment ofthe invention four bands of eyes 39 are provided at spaced apartintervals for facilitating securing of the belt 25 to torsos 3 ofdifferent girth about the waist.

[0136] An electrically conductive main contact means, namely, anelectrically conductive main contact 45 is located on the belt 25centrally in the main locating area 31 for applying one or more pulsedsignals generated by the signal generator 28 to the central electrode26. A pair of secondary contact means provided by electricallyconnective secondary contacts 46 are located in the respective sets ofsecondary locating areas 32 for applying signals generated by the signalgenerator 28 to the respective side electrodes 27. Each secondarycontact 46 is located in the sets of secondary locating areas 32 in sucha way that irrespective of which of the secondary locating areas 32 isselected for receiving the side electrode 27 the side electrode 27 isalways in contact with the corresponding secondary contact 46.

[0137] A reference means for locating the belt 25 relative to ananatomical reference, namely, the umbilicus in this embodiment of theinvention is provided by the main locating area 31, and in turn thecentral electrode 26 for locating the belt 25 on the torso 3. Thecentral electrode 26 when it is centrally located in the main locatingarea 31 is provided in a position so that when the belt 25 is secured tothe torso 3 with the central electrode 26 centrally located on theumbilicus 12 the belt 25 is centrally located circumferentially andvertically on the torso 3. Thus, when the belt 25 is tightly securedaround the torso 3 the side electrodes 27 are relatively accuratelylocated over or relatively close to the mid-axillary lines 13 and 14centrally between the rib cage 6 and the respective left and right iliaccrests 8 and 9.

[0138] In order that the belt 25, and in turn the central and sideelectrodes 26 and 27 are tightly secured to the subject, and also tofurther accommodate varying girths of torso 3, the belt 25 is of aresilient elasticated material for facilitating stretching of the belt25 between the respective ends 35 and 36. However, to further facilitatein accommodating torsos 3 of different girths, portions 47 betweenbroken lines 48, see FIG. 3 of the belt 25 on respective opposite sidesof the main locating area 29 and between the nearest secondary locatingareas 32 a are more resilient than the rest of the belt 25 foraccommodating extra stretchability of the belt 25 in the resilientportions 47. This, further facilitates in aligning the side electrodes27 with the respective left and right mid-axillary lines 13 and 14.

[0139] The belt 25 comprises a pair of outer layers 49 of stretchabletextile material, and an inner layer 50 of stretchable foam materialwhich are secured together by an edging braid 51 extending on respectiveopposite sides of the belt 25 and stitched to the outer layers 49 andthe inner layer 50. The braid 51 is also of a stretchable material, andthe stitching of the braid 51 to the outer and inner layers 49 and 50,respectively is arranged for providing greater stretchability in theresilient portions 47 than in the rest of the belt 25.

[0140] A receiving means in this embodiment of the invention provided bya receiving bracket 54 of plastics material is secured to the outer side40 of the belt 25 for releasably securing the signal generator 28 to thebelt 25. Guide tracks 55 in the receiving bracket 54 engagecorresponding guide grooves 56 on the signal generator 28 with a snapfit action for releasably and securely retaining the signal generator 28in the receiving bracket 54. A three contact jack plug 57 located in thereceiving bracket 54 engages a corresponding three contact jack socket58 in the signal generator 28 for connecting the signal generator 28 tothe central and side electrodes 26 and 27.

[0141] Main and secondary connecting means, namely, main and secondarycables 59 and 60, respectively, extending from the jack plug 57 arerespectively connected to the main contact 45 and the secondary contacts46. The main and secondary cables 59 and 60 are located between theouter layers 49 of the belt 25, and the secondary cables 60 are providedin consertina shape for facilitating expansion of the resilient portions47 of the belt 25. Control buttons 62 are provided on the signalgenerator 28 for operating corresponding control switches within thesignal generator 28 for controlling the signals generated by the signalgenerator 28 as will be described below.

[0142] Turning now to the central and side electrodes 26 and 27, andreferring in particular to FIGS. 7 to 9 the electrodes 26 and 27 areformed from electrically conductive foil 65. A first electricallyconductive means comprising a first electrically conductive adhesive gelcoating 67 is provided on one side 66 of the foil 65 for securing therespective central and side electrodes 26 and 27 to the belt 25 and forproviding electrical continuity between the foil 65 of the electrodes 26and 27 and the corresponding main or secondary contacts 45 and 46,respectively. A second electrically conductive means, namely, asecondary electrically conductive adhesive gel coating 68 is provided onthe other side 69 of the foil 65 for adhering the electrodes 26 and 27to the skin of the subject and for providing good electrical continuitybetween the respective electrodes 26 and 27 and the skin of the subject.In this embodiment of the invention in order to further enhanceelectrical continuity between the foil 65 of the electrodes 26 and 27and the corresponding main and secondary contacts 45 and 46 the firstadhesive coating 67 includes an electrolyte. Additionally, the adhesionstrength of the first adhesive coating 67 to the belt 25 is greater thanthe adhesion of the second adhesive coating 66 to the skin of thesubject for facilitating removal of the belt 25 and the electrodes 26and 27 from the subject without causing detachment of the electrodes 26and 27 from the belt 25.

[0143] In this embodiment of the invention the central electrode 26 isof dimensions 100 mm±20% in width in a circumferential direction aboutthe torso 3, and 100 mm±50% height in a vertical direction. The sideelectrodes 27 are respectively of 75 mm height±20% by 100 mm wide±20%.Central and side electrodes 26 and 27 of these dimensions have beenfound to be of sufficient size so that the central electrode 26 whencentrally applied over the umbilicus extends across a substantialportion of the rectus abdominis and the side electrodes 27 when locatedcentrally on the mid-axillary lines 13 and 14 or relatively closethereto covers a sufficient area of the lower thoracic nerves and thefirst and second lumbar nerves for providing stimulation of the rectusabdominis muscles and the transversalis and oblique muscles.

[0144] The central and side electrodes 26 and 27 are supplied withrelease sheets (not shown) on respective opposite sides thereof forprotecting the respective first and second adhesive coatings 67 and 68.

[0145] Referring now to FIGS. 13 to 18 various pulsed signals which canbe generated by the signal generator 28 and various connections of themain and central electrodes 26 and 27 to the pulse generator 28 will nowbe described. Referring initially to FIGS. 13 and 14 in this connectionconfiguration the respective left and right side electrodes 27 a and 27b which are also designated with the reference letters L and R,respectively, are independently connected to the pulse generator 28, andindependently apply respective pulsed signals l₁ and l₂ to the subjectwhich are generated by the pulse generator 28. The central electrodes 26which is designated in the reference letter U, acts as a common returnelectrode for returning the sum l₃ of the pulsed signals l₁+l₂ to thesignal generator 28, where l₃=l₁+l₂. Accordingly, in this configurationthe electrodes 26 and 27 are selected in pairs where one pair is formedby the central electrode 26 and one of the side electrodes 27, and theother pair is formed by the central electrode 26 and the other of theside electrodes 27. In other words the electrode pairs are the pairs R-Uand L-U.

[0146] In this embodiment of the invention the duration of the pulses ofeach pulsed signal which is applied to the respective pairs ofelectrodes may be independently varied between 50 microseconds and 1000microseconds. The interval between pulses of the pulsed signals may alsobe independently varied between 5 milliseconds and 1000 milliseconds.The magnitude M of the pulses of each pulsed signal l₁ and l₂ isindependently variable by the signal generator 28, and may range from 0mA to 100 mA. The pulses of the respective pulsed signals l₁ and l₂ arein phase, and thus, the pulses being returned to the signal generator 28through the central electrodes 26 is the sum of the outgoing pulses l₁and l₂.

[0147] Two of the control buttons 62 on the signal generator 28 providesfor manual independent varying of the magnitude M of the pulses of therespective pulsed signals l₁ and l₂, and another of the buttons 62 onthe signal generator 28 provides for balancing of the magnitude of thepulses of the respective pulsed signals. A further two of the buttons 62on the signal generator 28 provides for varying the interval betweenpulses of the pulsed signals. The duration of the pulses of each pulsedsignal is varied by another two of the buttons 62 on the signalgenerator 28. The control of the magnitude, the interval between thepulses and the duration of the pulses by the signal generator 28 willnot be described further, since the generation and control of suchpulsed signals will be well known to those skilled in the art.

[0148]FIGS. 15 and 16 illustrate an alternative connection configurationof the central and side electrodes 26 and 27 to the signal generator 28.In this configuration the electrodes 26 and 27 are selected in similarpairs as those described with reference to FIGS. 13 and 14, namely, thepairs R-U and L-U. However, only one pulsed signal l₃ is generated bythe signal generator 28 and is applied to the two side electrodes 27 aand 27 b, and returned through the central electrode 26 which acts as acommon return. In this embodiment of the invention the respectiveproportion l₁ and l₂ of the pulsed signals flowing through the sideelectrodes 27 a and 27 b may be similar or different, depending on theimpedance between the respective side electrodes 27 and the centralelectrode 26 through the subject, and the impedance between therespective side electrodes 27 and the skin of the subject. The magnitudeof the pulses are varied by one of the buttons 62 on the signalgenerator 28.

[0149] Referring now to FIGS. 17 and 18 there is illustrated a furtheralternative connection configuration of the central and side electrodes26 and 27 to the signal generator 28, and alternative pulsed signalsgenerated by the signal generator 28. In this configuration theelectrodes 26 and 27 are selected in pairs similar to those describedwith reference to FIGS. 13 and 14, namely, the pairs R-U and L-U. Thesignal generator 28 generates two pulsed signals l₁ and l₂ which areapplied respectively to the side electrodes 27 a and 27 b and arereturned through the central electrode 26 which acts as a common return.The pulses of the pulsed signals l₁ and l₂ in this case are 180° out ofphase with each other, however, the interval between the pulses of therespective pulsed signals is similar. The magnitude and duration of thepulses of the respective pulsed signals are independently variable, andas can be seen in FIG. 18 the pulses of the pulsed signal l₁ are ofgreater magnitude but shorter duration than the pulses of the pulsedsignal l₂.

[0150] In use, with the belt 25 laid flat and the inner side 34 facingupwardly the central electrode 26 is secured centrally in the mainlocating area 31. The appropriate secondary locating area 32 a, 32 b or32 c is selected, depending on the girth of the torso 3 of the subject,and the respective side electrodes 27 are secured to the inner side 34of the belt 25 with the peripheral edge 33 of the side electrodes 27aligned with the appropriate secondary locating marks 30 a, 30 b or 30c. Remaining release sheets are then removed from the central and sideelectrodes 26 and 27 and the belt 25 is offered up to the torso 3 of thesubject with the central electrode 26 centrally aligned with theumbilicus 12. The belt 25 is then stretched around the torso 3 of thesubject until the side electrodes 27 are centrally aligned with therespective left and right mid-axillary lines centrally between the ribcage 6 and the respective left and right iliac crests or relativelyclose thereto. The belt 25 is then secured to the subject by the band ofhooks 38 engaging the appropriate band 39 of eyes. FIGS. 11 and 12illustrate the preferable locations of the central electrode 26 and theside electrodes 27 on the torso 3 when the belt 25 is tightly secured tothe torso 3.

[0151] The signal generator 28 is then activated, and the desired pulsedsignal or signals are selected. If the signal generator 28 is operatedto provide two independent pulsed signals, the magnitude and/or durationof the pulses of the respective pulsed signals as the case may be isadjusted to the desired level, and the interval between pulses incertain cases may be adjusted. The pulsed signals may also be balancedas desired.

[0152] It has been surprisingly found that by centrally locating thecentral electrode 26 over the umbilicus so that the central electrode 26extends around the umbilicus 12, and by providing the side electrodes 27centrally aligned with the mid-axillary lines, centrally between the ribcage 6 and the corresponding left and right iliac crests, or between theumbilicus and the mid-axillary line towards the mid-axillary line, onlythree electrodes are required for providing adequate stimulation of therectus abdominis muscle and the transversalis and oblique muscles fortoning the muscles.

[0153] Referring now to FIGS. 19 to 27 there is illustrated a deviceaccording to another embodiment of the invention which is indicatedgenerally by the reference numeral 75 for stimulating the abdominalmuscles for toning thereof. The device 75 is substantially similar tothe device 1, and similar components are identified by the samereference numerals. The main difference between the device 75 and thedevice 1 is that instead of providing a single main locating area, apair of main locating areas, namely, a first main locating area 76 and asecond main locating area 77 are provided for locating respective firstand second central electrodes 78 and 79, respectively on the belt 25 forlocation respectively above and below the umbilicus 12. Otherwise, thedevice with the exception of the signal generator 28 is similar to thedevice 1. The first and second main locating areas 76 and 77, and inturn the first and second central electrodes 78 and 79 act as thereference means for locating the belt 25 on the torso 3. The belt 25 islocated on the torso 3 with the umbilicus 12 located centrally betweenthe respective first and second main locating areas 76 and 77, see FIGS.20 and 21.

[0154] Referring now to FIGS. 22 to 27 alternative connectingconfigurations for connecting the electrodes 78, 79 and 27 to the signalgenerator 28 are illustrated for applying the pulsed signals to thesubject through the electrodes 78, 79 and 27. The left and right sideelectrodes 27 a and 27 b are designated by the reference letters L andR, respectively, and the first and second central electrodes 78 and 79are designated by the reference letters U1 and U2, respectively. In FIG.22 the first and second electrodes 78 and 79 and the side electrodes 27are connected such that the side electrodes 27 and the first centralelectrode 78 effectively form one single electrode, while the secondelectrode 79 forms the other electrode, namely, the return electrode. Inthe connecting configuration of FIG. 23 the electrodes 78, 79 and 27 areconnected such that the side electrodes 27 are connected together andthe first and second central electrodes 78 and 79 are independentlyconnected to the signal generator 28. In this way the electrodes areselected in pairs such that one selected pair of electrodes is formed bythe side electrodes 27 which effectively act as one electrode and thesecond central electrodes 79 which acts as a return electrode, and theother selected pair of electrodes comprises the first central electrode78 and the second electrode 79, which also acts as a return electrodefor that selected pair of electrodes. In other words the pairs ofelectrodes are the pairs (RL)-U2 and U1-U2. A first pulsed signal isapplied to the selected electrode pair comprising the side electrodes 27and the second central electrode 79, and a second pulsed signal isapplied to the selected electrode pair comprising the first and secondcentral electrode 78 and 79. The first and second pulsed signals may beidentical or different and may be independently varied as discussed withreference to FIGS. 13, 14, 17 and 18.

[0155] Referring now to FIG. 24 there is illustrated a furtheralternative connection configuration of the first and second centralelectrodes 78 and 79 and the side electrodes 27 to the signal generator28. In this configuration the electrodes are selected in the followingpairs. One selected pair comprises the side electrodes 27 a and 27 bwhereby one of the side electrodes, namely, the left side electrode 27 aacts as the return electrode, and the other electrode pair is selectedfrom the first and second central electrode 78 and 79, whereby thesecond central electrode 79 acts as the return electrode. In other wordsthe electrode pairs are the pairs R-L and U1-U2. In this connectionconfiguration the signal generator generates two pulsed signalsindependently of each other, one of which is applied to the subjectthrough the side electrodes, while the other is applied to the subjectthrough the first and second central electrodes 78 and 79. The twopulsed signals may be the same or different, however, in order to avoida signal which is applied to the side electrode 27 b being returnedthrough the second electrode 79, and similarly, in order to avoid asignal applied to the first central electrodes 78 being returned throughthe side electrode 27 a, the signals are multiplexed to the electrodes,and preferably, are 180° out of phase.

[0156] Referring now to FIGS. 25 there is illustrated a schematicrepresentation of various electrode pairs which may be selectivelyselected from the first and second central electrodes 78 and 79 and theside electrodes 27 to the signal generator 28. In this embodiment of theinvention the electrodes may be selectively selected in electrode pairsas follows: R-U1 L-U2 R-U2 R-L L-U1 U1-U2

[0157] The subcutaneous currents which are passed through the subjectbetween the respective first and second central electrodes 78 and 79 andthe side electrodes 27 are illustrated in FIG. 25 and designated as RU1,LU1, RU2, LU2, RL and U1U2, and are also designated by the Romannumerals I to VI. The signals generated by the signal generator 28 maybe applied to the first and second central electrodes 78 and 79 and theside electrodes 27 in any or all of the six electrode pairs, and may beapplied sequentially, simultaneously, or partly simultaneously andsequentially to the electrode pairs in any order for selectivelystimulating the abdominal muscles. The signals may be multiplexed to theselected electrode pairs, and the signals applied to the respectiveelectrode pairs may be different for providing different stimulation tothe various abdominal muscles.

[0158] Referring now to FIG. 26 there is illustrated a circuitarrangement for applying signals to the subject through some or all ofthe electrode pairs selected from the electrodes 78, 79 and 27 describedwith reference to FIG. 25. In this embodiment of the invention thesignal generator 28 is provided with a pair of pulse generators, namely,a first pulse generator 90 and a second pulse generator 91, which applyrespective pulsed signals to the first and second central electrodes 78and 79 and the side electrodes 27 through a selecting means, namely, amatrix of switches S1 to S16. The pulsed signal from the first pulsegenerator 90 is applied to the electrode 78, 79 and 27 through theswitches S1 to S8, while the pulsed signal from the second pulsegenerator 91 is applied to the electrodes 78, 79 and 27 through theswitches S9 to S16. A microprocessor (not shown) in the signal generator28 selectively operates the switches S1 to S16 for selecting theelectrode pairs and for applying the respective pulsed signals from thefirst and second pulse generators 90 and 91 to the first and secondcentral electrodes 78 and 79 and the side electrodes 27 in some or allof the selected pairs described with reference to FIG. 25. The switchesS1 to S10 may be relays or semiconductor switches, and in certain casesmay be manually operated switches. The microprocessor (not shown) alsocontrols the first and second pulse generators 90 and 91 for determiningthe signals to be generated by the respective pulse generators so thatthe signals outputted by the pulse generators 90 and 91 may be variedfor applying different pulsed signals to the different selected pairs ofelectrodes for providing different levels of stimulation for the variousmuscles of the abdomen. Thus, the subcutaneous current paths through thesubject are selectable by selecting the appropriate electrode pairs, andthe signal to be passed through each current path is also selectable.Thus, the current distribution and effective pulse frequency at eachelectrode can be optimised for the tissue it is desired to stimulate.

[0159]FIG. 27 illustrates an alternative circuit arrangement forapplying signals generated by the signal generator 28 to the first andsecond central electrodes 78 and 79 and the side electrodes 27. Thiscircuit comprises a selecting means provided by switches S1, S2 and S3for applying the signals generated by the signal generator 28 to theelectrodes 78, 79 and 27. The switches S1, S2 and S3 provide for theselective selection of the electrodes in the following electrode pairs:R-U1 R-U2 L-U1 U1-U2 L-U2

[0160] A microprocessor (not shown) in the signal generator 28 controlsthe switches S1, S2 and S3, and the pulsed signals are multiplexed froma pulse generator 74 within the signal generator 28 through the switchesS1, S2 and S3 under the control of the microprocessor (not shown). Theswitches S1, S2 and S3 may be relays or semiconductor switches. When theswitches S1 and S2 are closed, and the switch S3 is closed onto thecontact (a) the current paths I, II, III and IV are enabled. When theswitch S3 is closed onto the contact (b) the current path V is enabled.In this circuit arrangement there is no provision for selecting theelectrode pair RL for providing the current path VI.

[0161] It has been found that by providing first and second centralelectrodes, with the first central electrode being located just abovethe umbilicus and the second central electrode located just below theumbilicus in certain circumstances stimulation of the rectus abdominismuscles is enhanced.

[0162] Referring now to FIGS. 28 to 30 there is illustrated a deviceaccording to a still further embodiment of the invention indicatedgenerally by the reference numeral 80 for stimulating abdominal musclesof a subject. The device 80 is substantially similar to the device 1,and similar components are identified by the same reference numerals.The main difference between the device 80 and the device 1 is that inthis embodiment of the invention main and secondary fastening meanscomprising main and secondary stud fasteners 81 and 82 are provided forfastening the respective electrodes 26 and 27 to the main and secondarylocating areas 31 and 32. In this embodiment of the invention each studfastener 81 and 82 comprises a female part 83 and a male part 84. Themale parts 84 are secured to and in electrical engagement with theelectrodes 26 and 27, while the female parts 83 are secured to the belt25 and provide electrical continuity between the electrodes 26 and 27and the signal generator 28 through corresponding main and secondarycables 59 and 60.

[0163] In this embodiment of the invention one of the female parts 83 ofthe secondary stud fasteners 82 is provided in each of the threesecondary locating areas 32 a, 32 b and 32 c for receiving the maleparts 84 with the corresponding side electrodes 27 in the desiredsecondary locating area 32. The female and male parts 83 and 84 of thestud fasteners 81 and 82 are of electrically conductive material, inthis case chrome plated steel. An electrically insulating coating 85 isapplied over a surface 86 of each female part 83 which is exposed, andwhich would be likely to come into contact with the skin of a subject ifit were not covered by one of the side electrodes 27. This, thus, avoidsany danger of a signal applied to the female part 83 of a secondary studfastener 82 by the signal generator 28 being transferred directly to thesubject from the surface 86 of the female part 83. However, the interiorof a socket 87 of each female part 83 provides good electricalcontinuity with a corresponding male projection 88 from thecorresponding male part 84 for ensuring electrical continuity betweenthe female and male parts 83 and 84 of the stud fasteners 81 and 82.

[0164] Use of the device 80 is similar to that of FIG. 1 once thecentral and side electrodes 26 and 27 have been secured to the belt 25by the stud fasteners 81 and 82.

[0165] While the central and side electrodes have been described ascomprising an electrically conductive adhesive coating on the side ofthe electrodes for adhering the electrodes to the skin of the subject,it is envisaged in certain cases that the electrically conductivecoating may be non-adhesive, and indeed, may be of the type which wouldprovide a low friction surface. In certain cases, it is envisaged thatsuch an electrically conductive coating may provide adequate electricalcontact between the electrodes and the subject.

[0166] While the device has been described for stimulating abdominalmuscles, it will be apparent to those skilled in the art that the deviceby suitably adapting the attachment means may be used for stimulatingother muscle groups of a subject, for example, back muscles, legmuscles, arm muscles, or indeed any other muscle group.

[0167] It will of course be appreciated that as well as being able tovary the current, duration of the pulses, the interval between thepulses, and/or other parameters of the pulsed signal, the direction ofthe current through the subcutaneous paths of the subject may also bereversed. It will of course be appreciated that any or all of thesubcutaneous current paths which may be selected by appropriatelyselecting the electrodes in appropriate selected pairs may be selectedin any order, and the order and selection may vary during a treatmentregime by suitably programming the microprocessor in the signalgenerator.

What is claimed is:
 1. A method for stimulating abdominal muscles of a subject, comprising the steps of: selecting at least two of at least three electrodes, one of the at least three electrodes being a central electrode located adjacent the umbilicus of the subject, and the other two electrodes being side electrodes located on the subject spaced apart from the central electrode on respective sides thereof in a general direction towards a corresponding one of the left and right mid-axillary lines of the torso intermediate the rib cage and corresponding left and right iliac crests; and passing at least one pulsed signal subcutaneously through the subject between the selected electrodes.
 2. The method as claimed in claim 1, wherein each side electrode is located towards the mid-point of the corresponding mid-axillary line between the rib cage and the corresponding iliac crest.
 3. The method as claimed in claim 1, wherein each side electrode is located adjacent the corresponding mid-axillary line.
 4. The method as claimed in claim 3, wherein each side electrode is located adjacent the mid-point of the corresponding mid-axillary line between the rib cage and the corresponding iliac crest.
 5. The method as claimed in claim 1, wherein the central electrode is located on the umbilicus and extends around the umbilicus.
 6. The method as claimed in claim 1, wherein the central electrode is located on the umbilicus and extends completely around the umbilicus.
 7. The method as claimed in claim 1, wherein the central electrode is located on the umbilicus, but with a greater area of the central electrode located below the umbilicus than above the umbilicus.
 8. The method as claimed in claim 1, wherein the central electrode is located adjacent but not on the umbilicus.
 9. The method as claimed in claim 1, wherein the central electrode is located below the umbilicus.
 10. The method as claimed in claim 1, wherein the central electrode is located above the umbilicus.
 11. The method as claimed in claim 1, wherein the central electrode is located both below and above the umbilicus.
 12. The method as claimed in claim 1, wherein the central electrode is formed as two electrodes, namely, a first central electrode and a second central electrode, both of which are located adjacent the umbilicus.
 13. The method as claimed in claim 12, wherein the first central electrode is located above the umbilicus and the second central electrode is located below the umbilicus. 